document result of running save-config in a tracker home directory

Author: rouilj

doc/admin_guide.txt

@@ -232,8 +232,12 @@ roundup-server command line use::
 
 Note it will save an old config.ini file to config.bak and create a
 new config.ini. The file is recreated from scratch ignoring the
-contents of the current config.ini. You may need to merge the
-backup and config files.
+contents of the current config.ini. You may need to merge the backup
+and config files. save-config doesn't attempt to load or verify an
+existing config.ini. Running this in a tracker home directory will
+move the exsiting config.ini to config.bak and replace it with the
+roundup-server's config.ini. This will make the tracker in the
+directory fail to start util the original config.ini is restored.
 
 Configuring Compression
 =======================

share/man/man1/roundup-server.1

@@ -78,7 +78,12 @@ Print version and exit.
 Print help and exit.
 .TP
 \fB--save-config\fP
-Create or update configuration file and exit.
+Create configuration file and exit. The old config.ini will be saved to
+config.bak. Note that this command doesn't attempt to load or verify
+an existing config.ini. Running this in a tracker home directory will
+move the existing config.ini to config.bak and replace it with the
+roundup-server's config.ini. This will make the tracker in the
+directory fail to start until the original config.ini is restored.
 .TP
 \fBname=\fP\fItracker home\fP
 Sets the tracker home(s) to use. The \fBname\fP variable is how the tracker is